While trying to get to the bottom of the wobbly idle issue with my 1983 300TD wagon, a seasoned mechanic told me that the wobble was likely a worn spring inside the injection pump and that it was nothing to worry about. However I was noticing harder and smokier cold and hot starts, and it seemed to make a slapping/nailing sound in sync with the wobble. I figured a diesel purge wouldn't hurt-- and sure enough it seemed to cure the hot start issues I was having as well as gain some smoothness at idle and power in general. At least temporarily. The starting began getting worse again a couple days later when we took the wagon on a 240mi road trip from LA to Sequoia/Kings Canyon NP, so I began considering springing for some Monark nozzles and a pop tester.

But first thing first, I decided to pony up for a diesel engine compression tester to assess the health of my 252,000 mi om617.

What I found was the following:

#1: 320psi
#2: 285-290psi (2 tries)
#3: 355psi
#4: 310psi
#5: 190-180psi (2 tries)

I also noticed that the injectors from cylinders 2 & 5 showed some interesting symptoms:

#2: what looked like a burn or rust mark on business-end of injector
#5: quite oily/wet, small bubbles

Finally, I decided to pop the cap off my coolant reservoir to check the level because my heater seemed to kick in and out intermittently during the trip. That's when I saw the dreaded black sludge (new!). I stuck a paper towel down for a sample and probed it with my finger (latex gloves on), and it seemed to me that it was indeed oil.

My guess is that I probably blew the head gasket going up and down the grapevine, then up and down the mountain roads in the NP. I had previously replaced the radiator about 2k miles ago and replaced some leaky coolant hoses right before the trip with no sign of oil at those times.

Given the likely $2k + bill to replace a head gasket and the uncertainty of whether the oil is coming from the head or past worn rings, I've been considering springing for a nice used 952 motor-- but am wary of committing to that without compression numbers or service history for fear of ending up with a similar result after 10k miles (or who knows how many). No motor I have seen on the market has compression numbers listed, so I would like to know if there are some reputable used engine resellers in the greater Los Angeles area that could gain me some peace of mind.

Either that or I go with a Metric Motors long block... but... $$$$

Tempted though...

I just acquired the wagon 11 months ago and have been putting a lot of work into it. Sadly this is a new issue after 4k miles of ownership and I am facing some pretty tremendous sunk cost if I cut bait, so that option is pretty much out. Plus I love owning this wagon and have wanted one since I first drove one almost 18 years ago

What would y'all do in this kind of situation?

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